fix(typecheck): regenerate route types and skip stale dev validator

`npm run typecheck` failed with 8 TS2307 errors from Next's generated
route validators referencing old page paths (e.g. calendar/page.js) after
routes moved to catch-all segments. Two causes:

- The production validator (.next/types) was stale. Prepend `next typegen`
  so `tsc` always runs against freshly generated route types.
- The dev validator (.next/dev/types) is a turbopack-dev-only artifact that
  is absent from clean/CI checkouts and goes stale locally. `next typegen`
  force-re-adds it to tsconfig `include`, so exclude it instead (exclude
  overrides include), leaving route typing to the maintained .next/types.

tsc still catches real type errors; verified `npm run typecheck` is clean
and idempotent.

package.json

@@ -30,7 +30,7 @@
     "test:translations": "vitest run --no-isolate lib/__tests__/translations.test.ts",
     "test:integration": "bash integration/run-tests.sh",
     "prepare": "husky",
-    "typecheck": "tsc --noEmit"
+    "typecheck": "next typegen && tsc --noEmit"
   },
   "dependencies": {
     "@dnd-kit/core": "^6.3.1",

tsconfig.json

@@ -39,6 +39,7 @@
     "node_modules",
     "repos",
     "examples",
-    "integration"
+    "integration",
+    ".next/dev/types"
   ]
 }